+
−.. -*- coding: utf-8; -*-
+
−
+
−=====
+
− GCC
+
−=====
+
−.. contents::
+
−   :local:
+
−
+
−Remove dead code
+
−================
+
−
+
−  STRIP_DEAD_CODE = -Wl,-static -fvtable-gc -fdata-sections -ffunction-sections -Wl,--gc-sections -Wl,-s
+
−
+
−  -Wl,-static
+
−                Link against static libraries. Required for dead-code
+
−                elimination.
+
−
+
−  -fvtable-gc
+
−                C++ virtual method table instrumented with garbage collection
+
−                information for the linker.
+
−
+
−  -fdata-sections
+
−                Keeps data in separate data sections, so they can be discarded
+
−                if unused.
+
−
+
−  -ffunction-sections
+
−                Keeps funcitons in separate data sections, so they can be
+
−                discarded if unused.
+
−
+
−  -Wl,--gc-sections
+
−                Tell the linker to garbage collect and discard unused
+
−                sections.
+
−
+
−  -s
+
−                Strip the debug information, so as to make the code as small
+
−                as possible. (I presume that you'd want to do this in a
+
−                dead-code removal build.)
+
−
+
−Map file
+
−========
+
−::
+
−
+
−  $ ld -Map=file.map <opts> <files>
+
−
+
−or::
+
−
+
−  $ gcc -Wl,-Map=file.map <opts> <files>
+
−
+
−Predefined macros
+
−=================
+
−::
+
−
+
−  $ gcc -arch ppc -dM -E - < /dev/null | sort
+
−
+
−Default search path
+
−===================
+
−
+
−  $ echo | gcc -v -x c -E -
+
−
+
−  $ gcc -print-search-dirs
+
−  install: ...
+
−  programs: ...
+
−  libraries: ...
+
−
+
−Use -### in actual invoking::
+
−
+
−  $ gcc -### -o foo foo.c
+
−
+
−  $ ld --verbose | grep SEARCH_DIR
+
−
+
−``LIBRARY_PATH`` and ``LD_LIBRARY_PATH``::
+
−
+
−  $ cpp -Wp,-v
+
−  $ cpp -Wp,-lang-c++,-v
+
−  $ cpp -x c++ -Wp,-v
+
−